Heat regulator



6. D. BOLIN HEAT REGULATOR June 13, 19 33.

Filed April 28. 1932 Fig.3. 28

Inventor WQ m H n u:

@m gfldg, By

Att'y ama June 13, 1933 1). Bonus, or s'rQLoms, inssom momma ap lmuo ma April as,

My invention relates to oven heat control devices and more particularly to improve-- mentsin mechanism for actuating the fuel su ply valve.

ne of the objects of my invention is to Provide a device in which the fuel supply 1s controlled by. bowed thermally responsive element having its'ends interposed between the'valve and an abutment spaced from the valve in the direction of the valve movement, whereb increase or decrease in curvature of the e ement will, through the resultant variation in the distance between its ends, determine the position of the valve with respect to its seat. I prefer to employ asthe thermally responsive element, bimetallic strips formed of two metals having different coeflicients of expansion. And. a further object of my invention is to construct asimple, compact, inexpensive and eflicient device embodying this type of valve controllin element.

Other jects will become apparent from the following description of a single embodiment of my invention taken in connection with the accompanying drawing in which Figure 1 is a front elevationof a gas stove, partly in section, showin my im roved heat' control device installed t erein; igure 2 is a cross sectional view of the fuel valve and the thermo-sensit ive control means; Figure 3 is a top view of the thermo-sensitive control means; and Figure 4 is a cross sectional view on the line 4-4 of Figure 2. 7

Referring to the drawing, the numeral 1 indicates t e oven portion and 2 the open burner section of a gas stove. .The oven burner 3 receives fuel from the manifold 4 by we of the pipe 5, the thermostatically contro ed valve 1n the casing 8, and the ipe .7. The controlling thermostat extends'mto the interior of the top of the oven andthe pipes 5 and 7'connected withthe valve are concealed in the space between the lining and the exterior casing of the oven.

Since the specific type ofvalve. forms no part of my invention, it need only. be briefly escribed. The casing 8 forthe valve 12 1s provided with a valve seat 9located between 50 the inlet and outlet chambers 10 and 11. The

ber 23 is was some Io. eo'mao.

outer side of the chamber 11 is formed by I cap 13 in threaded engagement with the casing1 body. A valve settin member 14 exten s through the cap an is provided with a slot 15 in its inner end for receiving 5 the flat projection 16 on the disc valve, whereby the valve ma be rotated with the setting member 14. suitable coil spring 17, interposed between the valve 12 and an annular shoulder 18. on the member 14, biases the disc valve towardjclosed position.- The exterior end of the setting member 14 1s govided with an indicating plate 19- and a ob 20, the indicating plate cooperating with suitable indicia adjacent an opening 21 in the cap 22 to thereby indicate the temperature of the oven for a particular setting of thevalve. a

The valve is screw-threaded to a member 23 which is provide cooperating with 9. pi 25 whereby the mem fprevented from rotation but without inter ering with itslongitudinal movement on the axis of the valve.

In accordance with the preferred embodi- 75 ment of my invention I provide the valve casing 8 with an integral extension 26 comprising a block portion 27 adjacent the valve casing and a pair of arms 28 provided with a cross bar 29 at their outer ends. bearing tube 30 extends through an opening in block portion 27, the opening being in alignment with the axis of the valve. A small rod 31, adapted to have snu sliding fit inthe bearing tube 30, abuts t e member 23 at one of its ends, the opposite end extendin into the s ace between the arms 28 and ing rovi ed with a thermostat engaging mem r 32. The cross bar 29 of the arms 28 carries an abutment 33 also pgovided with a thermostat engaging memr' 34, the member 34 being in axial alignment with the rod 31.

A pair of op ositely bowed thermostatic elements 35 an 36 are interposed between and in abutting enga ment-with the member 32 and the mem r 34. Each'of the thermostatic elements are formed b fusing or welding two metal strips having difi'erent with an extension 24 9 stri toget er the coefie ients of expans sion, as is well known in the construction of thermostatic elements of this type. The members 32 and 34 are each provided with a pair of notches 37 to receive the ends of the thermostatic elements 35 and 36 and these ends are provided with recesses 38, the bot toms of which cooperate with the bottoms of the notches 37. In order to insure that the thermostatic elements 35 and 36 will not have relative longitudinal movement with respect to the members 32 and 34:, when subject to changes in temperature, the surfaces d1 of the bottoms of the notches 37 are formed at right angles to the axis of the rod 31. The abutting ends of each of the elements 35 and 36, therefore, will at all times contact the surfaces &1 regardless or the amount of bowing of the elements.

The abutment 33 is connected to the cross bar 29 by a clamping screw 42 extending through slot 43, the abutment 33 being slidable in groove 4A: in the cross bar, thereby providing means by which the abutment can be moved to allow assembly and proper adjustment of the thermostatic elements 35 and 36 and of the valve opening.

4 When'the oven is cold, the thermostatic.

elements 35 and 36 will be in their normal bowed position and will maintain the valve in an open position against the actidn of spring 17, the magnitude of the clearance between the valve and its seat being determined by the dial setting selected. As the temperature ,of the oven increases, the bimetallic strips 35 and 36 will be bowed outwardly toward the arms 28 due to the difierence in the coeficients of expansion of the metals forming each strip, the strips being so formed that the metal on their concave sides has lower expansion coefficient than that on their convex sides. This bowing outwardly of the strips decreases the distance between the ends of each strip, thereby permitting the spring 17 to move the valve toward closed position. When the temperature of the oven has reached the value indicated by the indicating plate, the opening of the valve will be such as to allow suilicient fuel to pass to the burner 3 to maintain this temperature.

It will be noted that my improved thermostatic valve operating mechanism embodies no pivots or lost motion between parts and, therefore, the accuracy of its temperature control in accordance with dial settings, is not subject to being disturbed by shocks to the stove or to the portion projecting within the oven through contact with the cooking utensils inserted therein, and, also, that the use of bowed thermostatio strips in endwise relation to the valve operating rod permits the over-all length of the control device to be much shorter than that of devices in which the valve opening is controlled by difierences in linear expansion teasers of elements. It will be understood that a single bowed thermostatic element could be used, but the use of two such elements in the manner herein described, greatly improves the operation and sensitivity of the device in that thinner thermostatic strips may be employed without the thermostatic device may be distorted to the slightest degree by the pressure of the spring 17. 7

Having fully described my invention, what ll'claim as new and desire ta secure by Letters Patent of the United States is:

1. ln apparatus at the class described, the combination of a valve biased to closed osition, an abutment spaced from said vave in the direction, of its closing movement,

producing the condition that and temperature responsive means compms ing an element which bends under the influence of temperature changes and thereby variesthe distance between its ends, one of said ends'engaging said abutment and the other forming a sto for the valve.

2. In apparatus -0 the class described, the combination of a valve, a slidable member cooperating with said valve, an abutment spaced from said slidable member, a bowed t errnally responsive member interposed between and having one end bearing on the abutment and the other end being on the slidable member, said valve, slidable member, and the ends of said bowed member all being in longitudinal alignment, and a spring biasing the valve toward closed posit1on and maintaining the ends 0d the bowed member in contact with the slidable member and the abutment.

3. In apparatus of the class described, the combination of a valve, a slidable member engaging said valve, an abutment spaced from said slidable member, and a bowed thermostatic member interposed between and having its ends in contact with the abutment and the slidable' member, the surfaces on the abutment and the slidable member which are en aged by the ends of the thermostaticmem er being at right angles ta the axis of the slidable member.

4:. A thermo-sensitive unit comprising an abutment, a member movable toward and away from said abutment, and a pair of oppositely bowed elements inter osed between the movable member and the a utment, each element having one end engaging the movslidable member and the other end bearing on the abutment, the surfaces of the slidable member and the abutment which are enga ed by pig t angles to the axis of the slidable memer.

6. A thermo-sensitive unit comprising a movable member provided with a recess at one of its ends, an abutment axially spaced from the recessed end of the movable memher and also rovided'with a recess, and a bowed bimeta lic element composed of materials having different coefiicients of expan-' sion interposed between the movable memher and the abutment and provided with a recess at each end, the recess on the abut ment and the movable member being in interengagement with the recess on the adja cent end of the element.

7. Oven heat control apparatus comprisin a fuel supply valve, means biasing the valve toward closed position, an abutment spaced from the valve in the direction of its closing movement, and thermostatically controlled means for governing said movement, said means comprising a deformable element having an intermediate portion out of alignment with its ends, one of said ends bearing on the abutment member and the other forming a stop maintaining the valve in open position when the oven temperature is below a predetermined minimum.

In testimony whereof, I hereunto afiix my signature, this 26th day of April, 1932,

CHARLESD. BOLIN.

the ends of the element being at v 

